This invention relates to electrolytically refining mixtures of metals to recover predetermined metals and more particularly to the refining of a spent fuel utilizing a sequence of anode zones.
Electrorefining has been used in processes for recovering high purity metal or metals from an impure feed. In some instances, the electrorefining is carried out in an electrolysis cell in which the impure mixture forms the anode, the electrolyte is a fused salt of the metal or metals to be recovered plus an alkali metal halide, and the purified metal is recovered at the cathode. In some designs, the metal collected at the cathode collects at the bottom of the cell. In another proposed design as disclosed in U.S. Pat. No. 2,951,793, the anode is a liquid pool at the bottom of the cell and the cathode may be located above the anode.
While the anode pool has certain advantages, it is necessary for the spent fuel to be dissolved before the particular metal or metals may be transferred through the electrolyte to the cathode. In addition, the spent fuel usually has the outer cladding which is insoluble and tends to collect at the bottom of the cell. Accordingly, new designs of the cell are desirable to reduce the extent of some of these limitations in the general design.